Method of and means for forming gun barrels



m mmz July 10, 1923.

C. C. LOOMIS METHOD OF AND MEANS FOR FORMING GUN BARRELS INVENTOR. CRAWFORD O. LOOMIS." BY flw WITNESS ATTORNEY Patented July 10, 1923.

CRAWFORD C. LQOMIS, OF ILION, NEW YORK.

nin'rnon or AND MEANS non roma ne GUN BAnnnLs.

Application-filed January 8, 1921. Serial No. 435,811.

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To all whom it may concern.

Be it known that I, CRAWFORD (l-LooMIs, a citizen of the-United States, residing at Ilion, in the county of He'rkimer' and State of New York,'have invented a certain new and useful Improved Method of andMeans for Forming Gun Barrels, of which the following is a specification. 1

In breech loading firearms, particularly of the magazine loading type, whether manual or automatic, it is usually desirable to form the entrance to the cartridge chamber in the barrel with a flared approach to facilitate the entrance of the bullet of the cartridge into the chamber. In many such arms the cartridge is moved upward and forward from the magazine to the chamber and for this reason it is often necessary to elevate the bullet end of the cartridge into alignment with the chamber. This is usually done by cutting away part of the barrel chamber thereby providing a bullet incline along which the bullet may rise into the chamber.

The present invention relates to improved means for and method of forming gun barrels in this way and has for an object to accomplish this at a low cost and in such a way that the incline surface will merge gradually into the chamber surface.

Another object is to form such flared approach and bullet incline with the same tool and fixture.

A further object is to form the bullet incline by revolving the barrel about a transverse axis relative to a cutting tool'whereby the tool generates a bullet incline which merges gradually into the chamber surfaces. I y

For a full understanding of this invention reference is to be had to the attached drawing wherein,

Fig. 1 is a central longitudinal'sectional view of a partly finished barrel showing a cutting tool in position prior to forming the flared approach to the chamber.

Fig. 2 is a slightly enlarged view showing the tool after having formed such flared approach.

Fig. 3 is a similar view showing the barrel revolved to a position where the bullet incline has been formed.

Fig. 4 is a rear view of the finished barrel.

Fig. 5 is a longitudinal sectional view on a reduced scale of a finished barrel showing a cartridge in position in the chamber in dotted lines.

In said drawings, the numeral 6 indicates a gun barrel of any ordinary type, in the present instance the barrel of an automatic pistol'being illustrated. 7 is the bore of the barrel and 8 indicates the chamber. In barrels of this type a chamber is generally formed with a shoulder 8 against which the front end of the cartridge shell is seated. 9 indicates a usual form of barrel lug. Numeral 10 indicates any suitable revolving tool such as a milling cutter and is preferably of substantially the form shown.

As the first step of the process the tool 10 is moved toward the barrel or vice versa, the tool and barrel bore being coaxial. At the end of this step the tool 10 is in the position shown in Fig. 2 and has formed a substantially conical flared approach 11 to the chamber 8. As the second step of the process the barrel is revolved about the axis 12 (or the tool may be given a corresponding motion). The barrel and tool are relatively revolved until the parts are in the relative position shown in Fig. 3. This operation-results in the cutting away of the barrel material below the axis into substantially the form shown in Figs. 4 and 5 leaving a bullet incline 13 which merges grad- 35 ually into the flared approach 11. The lower part of the bullet incline, i. e. the part on which the tool is operating at the last part of its relative movement is aconical surface and its intersection with the rear end of the barrel is therefore an ellipse as shown in Fig. 4:. This ellipse gradually emerges into the circular section formed by the flared approach 11.

The form and dimension of the tool and the extent of revolution of the barrel relative to the tool shown in the drawings have been found to give very excellent results in practice, but it is to be understood that changes in the size and shape of the cutting tool and in the extent of its revolution relative to the barrel may be varied without departing from the invention as expressed in the following claims 1. In the manufacture of gun barrels, the process of forming a flared approach to the barrel and forming a bullet incline therein which consists in bringing a substantially conicalL cutting tool against the end of the barrel coaxially therewith to form said flared approach ancl then revolving the bar+ rel relatively to the tool about a transverse axis for forming the bullet'incline.

2. In the manufactureof gun barrels the process of forming a flared approach to the barrel and forming-a bullet incline therein which consists in bringing a substantially conical cutting tool against the end of the barrel to form said flared approach and then revolving the barrel relatively to the tool about a transverse aXis-for-forming thebul let incline.

3; In the manufacture of gun barrels; the process of forming a flared approach to the barrel and forming a bulletincline therein which consistsin bringing asubstantially. conical cutting tool against the end of the barrel to form said flarecl' approach and then moving the barrel relatively to the tool for forming the bullet incline.

4a, ln'tl'ieimanufacture of gun barrels, the process of forming a flared approach to the barrel and forming a bullet incline therein whichconsists, in, bringing a substantially conical cutting tool and the barrel together coaxia'lly for; formin'g said flared approach and then revolving the barrel and tool relatively to" each other; for forming the bullet incline.

5. In the manufactureof gun bar'relsrthe process of forminga flared approach to the barrel ancl forminga bullet" incline therein which consistsin bringing-a cutting tool and the barrel together for forming'saicl flared approach: and then revolving the barrel and tool relatively toeach other for forming the bullet incline.

CRAWFORD-Cl LOOMIS. 

